Dynamics NAV 2013 - How to page break at x lines - Row number, Row Count

Setup  a group at the highest level that groups on the detail line numbers. Use a value that allows an acceptable number of records to fall within each grouping.
Either one of these two methods can work depending on your needs.

• The Groupname must be the group directly above the group you are using the formula in. (The page break group should be the first group under the header you are using in the formula)
• Set the group to group on the formula below
• Save
• Remove the sorting option on the group

=Floor(Fields!Purchase_Line___Line_No__.Value / 1000000)

=Floor((rownumber("GroupName")-1) / 28)